International Journal of and Research, Int J Anat Res 2014, Vol 2(2):310-14. ISSN 2321- 4287 Original Article MORPHOLOGICAL STUDY OF HUMAN AND ITS SURGICAL IMPORTANCE Sachin Patil *1, Madhu Sethi 2, Smita Kakar 3. *1, 2 Senior Resident, 3 Director, Professor. Department Of Anatomy, Maulana azad medical college, New Delhi, India. ABSTRACT

Background: The liver is largest abdominal viscera located in right , and left hypochondrium in upper abdominal cavity. Although the segmental anatomy of the liver has been extensively researched, very few studies have dealt with surface variations of the liver. The major fissures are important landmarks for interpreting the lobar anatomy and locating the liver lesions. Purpose: The purpose of our study was to determine gross anatomical variations of liver and their clinical and surgical implications. Methods and Results: Present morphological study was conducted on 50 embalmed human in the Department of Anatomy, Maulana Azad Medical College, New Delhi,India. Different variations in lobes, fissures and accessory lobes or fissures were observed. The liver specimens were also classified according to netter’s six types of liver variations. Conclusion: The findings of our study may be helpful for surgeons and radiologist to avoid possible errors in interpretations and subsequent misdiagnosis, and to assist in planning appropriate surgical approaches. KEYWORDS: Liver, Quadrate, Caudate, Segment, Hepatectomy. Address for Correspondence: Dr Sachin.Patil, Department of Anatomy, Maulana Azad Medical College, Bahadhur shah zafar marg, New Delhi-110002, India. Phone: +919650844727. E-Mail: [email protected]

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Received: 28 March 2014 Peer Review: 28 March 2014 Published (O):30 April 2014 Accepted: 19 April 2014 Published (P):30 June 2014

INTRODUCTION of the liver is based on Couinaud’s division of the The liver is wedge shape ,largest abdominal liver into eight (subsequently nine) functional viscera, occupying a substantial portion of the segments, based upon the distribution of portal upper abdominal cavity. It occupies most of the venous branches and the location of the hepatic right hypochondrium and epigastrium, and veins in the parenchyma.[1] The major fissures frequently extends into the left hypochondrium are important landmarks for interpreting the as far as the left lateral line. The liver weighs lobar anatomy and locating the liver lesions. approximately 5% of the body weight in infancy With advancement of imaging and minimally- and it decreases to approximately 2% in invasive surgeries, it is essential for both the adulthood. The size of the liver also varies radiologists and operating surgeons to have a according to sex, age and body size. The liver is thorough knowledge of the anatomy and the anatomically divided into right, left, caudate and commonly-occurring variations of liver. Although quadrate lobes by the surface peritoneal and the segmental anatomy of the liver has been ligamentous attachments [1]. extensively researched, very few studies have Current understanding of the functional anatomy dealt with surface variations of the liver [2].

Int J Anat Res 2014, 2(2):310-14. ISSN 2321-4287 310 Sachin Patil et al., MORPHOLOGICAL STUDY OF HUMAN LIVER AND ITS SURGICAL IMPORTANCE. Defective development of the left lobe of liver Fig. 1: Liver Showing Accessory Fissure On Right Lobe. can lead to conditions like gastric volvulus while defective development of the right lobe can remain clinically latent or progress to portal hypertension. The anomalies related to excessive development of the liver lead to the formation of accessory which may carry the risk of torsion [3]. The aim of the study was to determine gross anatomical variations of liver and their clinical and surgical implications. MATERIALS AND METHODS AF-accessory fissure The study was conducted on 50 embalmed Fig. 2: Liver Showing Accessory Fissure On Caudate Lobe. human livers from in the Department of Anatomy, Maulana Azad Medical College, New Delhi, India. The liver specimens were removed from adult human cadavers during routine dissection for medical undergraduate students and then preserved in 10% of formalin. The lobes of the liver, right lobe, left lobe, caudate lobe, and quadrate lobe was studied in detail for the size, shape, accessory fissures, and accessory lobes and the specimens were photographed. All intact cadaveric liver with no obvious deformity studied. Liver with features of or any damage was excluded. RL-right lobe,LL-left lobe,CL-caudate lobe, AF-accessory OBSERVATIONS AND RESULTS fissure Out of the 50 specimens, in present study the Fig. 3: Liver Showing Pons Hepatis Connecting Left Lobe normal surfaces, fissures, and borders were With Quadrate Lobe. observed in 28 livers (56 %) without any accessory fissures or lobes .Out of the remain- ing 22 specimens, 5 (10%) specimens, even though they appear normal, they had accessory fissures on the different lobes, which resulted in the formation of accessory lobes. (Figure 1 & 2). Pons hepatis of variable size and shape joining the left lobe with quadrate lobe was seen in 5 (10 %) specimens (Figure 3). A complete transverse fissure dividing quadrate lobe into a superior and an inferior lobe (Figure 4 ) was seen in 2(4%) specimens while a mini accessory lobe above quadrate lobe was seen in 1(2%) specimen (Figure 5). Absence of fissure for ligamentum teres was seen in 2(4%) specimen (Figure 6) (Table 1). The liver specimens were also classified according to six types of liver varia- RL-right lobe,LL-left lobe,CL-caudate lobe, QL-quadrate tions (Figure 7-11) as described by Netter [11]. lobe, GB-gall bladder, PoH-pons hepatis (Table 2)

Int J Anat Res 2014, 2(2):310-14. ISSN 2321-4287 311 Sachin Patil et al., MORPHOLOGICAL STUDY OF HUMAN LIVER AND ITS SURGICAL IMPORTANCE.

Fig. 4: Liver Showing Acessory fissure with Superior And Fig. 8: Netter’s Type 3 liver -Transverse saddle like liver Inferior Quadrate Lobe. with relatively large left lobe.

RL-right lobe,LL-left lobe,CL-caudate lobe, SQL-superior quadrate lobe, IQL- inferior quadrate lobe ,GB-gall blad- RL-right lobe,FL-,LL-left lobe der, PH-, AF-accessory fissure. Fig. 9: Netter’s Type 4 liver showing tongue like process Fig. 5: Liver showing Mini Acessory Lobe. of right lobe.

RL-right lobe, LL-left lobe, QL-quadate lobe, MAL-mini accessory lobe, GB-gall bladder,PH- porta hepatis. DG-diaphragmatic groove-, RL-right lobe,LL-left lobe Fig. 6: Liver showing absence of fissure for ligamentum Fig. 10: Netter’s Type 5 liver showing very deep renal teres. impression and corset constriction.

Arrow Pointing To Absence Of Fissure For Ligamentum RL-right lobe,LL-left lobe,CL-caudate lobe, QL-quadrate Teres lobe Fig. 7: Netter’s Type 1 showing very small left lobe with Fig. 11: Netter’s Type 6 liver showing diaphragmatic deep costal impressions. grooves.

RL-right lobe,FL-falciform ligament,LL-left lobe,CI-costal Arrow Pointing to diaphragmatic grooves impression. Int J Anat Res 2014, 2(2):310-14. ISSN 2321-4287 312 Sachin Patil et al., MORPHOLOGICAL STUDY OF HUMAN LIVER AND ITS SURGICAL IMPORTANCE.

Table 1: Different morphological variations of liver. adjacent sagittal portal territories. These weak zones offer a lower resistance to external Morphological features Number of specimens pressure of the diaphragm. Macchi et al Normal 28 (56 %) suggested that the diaphragmatic sulci could Accessory Fissures And Lobes 5 (10%) represent a useful landmark for surface Pons Hepatis Connecting Left Lobe 5 (10 %) projection of the portal fissures and of the With Quadrate Lobe hepatic veins and their tributaries running Superior And Inferior Quadrate Lobe 2(4%) through them [6]. The mini accessory lobe which is being reported Table 2: Classification of liver according to Netter’s [11]. here is surgically and radiologically very Netter type Number of specimens important due to its small size. Due to the small Type 1 (Very small left lobe , deep costal 1(2%) size, it might be mistaken for a lymph node. It impressions) might be accidentally removed during the Type 2 (Complete atrophy of left lobe) - surgeries in and around the porta hepatis. A Type 3 (Transverse saddle like liver, relatively 5(10%) damage to the lobe or its vascular pedicle might large left lobe) Type 4 (Tongue like process of right lobe) 1(2%) result in bleeding into the abdominal cavity. Type 5 (Very deep renal impression and corset Accessory lobes need attention when there is 1(2%) constriction) torsion of the vascular pedicle or metastasis Type 6 (Diaphragmatic grooves) 1(2%) occurring in them. Torsion of the accessory lobes is a surgical emergency and it has to be attended DISCUSSION to early [7,8]. An accessory lobe could be formed The congenital malformations of the liver include by the displacement of the primitive rudiment agenesis of the lobes, absence of segments, of the , or by persistence of the deformed lobes, smaller lobes, atrophy of the mesodermal septa during its proliferation [9]. Its lobes and hypoplastic lobes. The anomalies of presence occurs due to an error in the formation liver can be either due to anomalies due to of the endodermal caudal and defective development or those due to excessive segmentation of the hepatic bud in the third development. These anomalies are sometimes month of the intrauterine life [7]. associated with malformations of other organs In the present study, accessory fissures were like diaphragm and suspensory apparatus of the seen on right lobe, quadrate lobe and caudate liver [3]. lobe According to Auh et al. the accessory The lobar and segmental anomalies are rarest hepatic fissures are potential sources of of all malformations. The embryological basis of diagnostic errors during imaging. Any collection the anomalies of liver morphology occurring in of fluid in these fissures may be mistaken for a the course of organogenesis remains to be liver cyst, intrahepatic haematoma or liver elucidated [4]. It has recently been reported that abscess. Implantation of peritoneally- some apparent morphological changes detected disseminated tumour cells into these spaces may during advanced imaging examinations may mimic intrahepatic focal lesions. Mazziotti et al actually be pseudolesions resulting from advocated the use of intraoperative perfusion defects, focal fatty infiltrations and ultrasonography in liver surgery to determine the other causes, and may not represent true anatomical location and the extent of the lesion, parenchymatous lesions [5]. thereby minimising unnecessary tissue The diaphragmatic sulci result from uneven dissections and traumatic surgical manoeuvres. growth of the hepatic parenchyma caused by Knowledge of such possible variations is variable resistance offered by different bundles important during radiological investigation and of the diaphragm muscle. But more recently, surgery [10]. radiological and corrosion cast studies have The different morphology of all lobes was noted attributed the formation of sulci to the existence in our study, and the presence of the pons of weak zones of hepatic parenchyma, hepatis bridging the fissure for ligamentum teres represented by the portal fissures between the are very important findings which was reported Int J Anat Res 2014, 2(2):310-14. ISSN 2321-4287 313 Sachin Patil et al., MORPHOLOGICAL STUDY OF HUMAN LIVER AND ITS SURGICAL IMPORTANCE. in previous study by Joshi et al. In cases of the [2]. Joshi SD, Joshi SS, Athavale SA. Some interesting pons hepatis bridging the fissure for ligamentum observations on the surface features of the liver teres, normal visualisation of the fissure would and their clinical implications, Singapore Med J 2009;50(7):715- 19. not be possible and dimensions of the right and [3]. Daver GB, Bakhshi GD, Patil A, Ellur S, Jain M, Daver the left lobes may be mistaken [2]. It has been NG. Bifid liver in a patient with diaphragmatic observed that on computed tomography, a hernia. Indian J Gastroenterol. 2005;24(1):27-8. normal-sized or small papillary process may be [4]. Champetier J, Yver R, Létoublon C, Vigneau B. A mistaken for enlarged porta hepatis nodes [10]. general review of anomalies of hepatic morphology and their clinical implications. Anatomia CONCLUSION Clinica,1985;7(4):285-299 [5]. Meirelles GSP, G. D’Ippolito .Liver pseudolesions in With advances in liver surgery like laparoscopic helical CT: pictorial essay. Radiol Bras. 2003; 36:229- hepatectomy and laparoscopic thermal ablation 35. for patients with hepatic tumour ,these [6]. Macchi V. Feltrin G. Parenti A. De Caro R. variations assume more importance . In Diaphragmatic sulci and portal fissures. J Anat. 2003; 202 (3):303-8. conclusion, this study highlights the frequent [7]. 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How to cite this article: Sachin Patil, Madhu Sethi, Smita Kakar. MORPHOLOGICAL STUDY OF HUMAN LIVER AND ITS SURGICAL IMPORTANCE. Int J Anat Res 2014;2(2):310-14.

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